Easy way to magnetic nanomaterials

Published online 8 September 2010

Mohammed Yahia

The produced aerogel has a high water retention capacity. A 60 mg sample can hold ~1 g of water.
Nature Nanotechnology

The magnetic properties of polymer–nanoparticle composites hold great potential in many applications, such as data storage and biomedicine. However, its production is complicated by the tendency of tiny particles to aggregate at high concentrations, which impedes the mechanical and magnetic properties of the material.

A team of researchers, including Azizi Samir, from Nanocomposites and Bioconcepts, a Moroccan biotech company, propose using a very thin nanofibril network of cellulose, extracted from bacteria or wood, as a matrix to precipitate cobalt ferrite nanoparticles.

They freeze-dried a bacterial cellulose gel to produce a cellulose nanofibril skeleton. Immersion in a solution of ferric cobalt under moderate temperatures precipitates ferrite crystals into this skeleton. The resulting, highly porous magnetic aerogel can be further dried and compacted into a high density, magnetic nanopaper. Small modifications to the concentration of the solution can change the properties of the nanoparticle structures produced, allowing for tailor-made size and strength.

This fairly easy technique can make inorganic/organic nanocomposites such as a flexible light aerogel or a stiff, strong nanopaper depending upon needs. As large quantities of cellulose are easily extracted from wood, this method could be suited for industrial-scale production. The researchers contend that these dynamic materials have a wide array of uses, from biological and medical fluidic applications to anti-counterfeit measures.